Japanese SEO Secrets: Google Algorithm and Japanese Content

Understanding Japanese SEO and Google's Algorithm

For Asian companies considering entry into the Japanese market and domestic SMBs looking to strengthen their web presence, understanding Japanese SEO is essential. While Google's search algorithm is built on technology developed for English-speaking markets, Japanese language processing presents unique complexities. Unlike English, where words are naturally separated by spaces, Japanese lacks word boundaries—requiring sophisticated language processing technology for search engines to accurately understand content.

This article provides a technical explanation of how Google's algorithm analyzes and evaluates Japanese content. We'll explore practical SEO strategies across five key areas:

1. Morphological analysis
2. Compound noun recognition
3. Character type balance
4. Heading hierarchy
5. E-E-A-T development.

Implementing these strategies correctly enables not only improved search rankings but also enhanced user experience and maximized business results.

How Morphological Analysis Engines Work

What Is Morphological Analysis?

Google's first step in understanding Japanese is morphological analysis. A morpheme is the smallest meaningful unit of language, and Google's algorithm segments Japanese text into morphemes to comprehend content meaning. While English words are naturally separated by spaces, Japanese operates differently. When encountering the string "検索エンジン最適化" (search engine optimization), humans can mentally divide it into three words—"検索" (search), "エンジン" (engine), and "最適化" (optimization)—but for machines, this segmentation is extremely complex. Google combines multiple language processing technologies to determine where word boundaries should occur.

How Morphological Analysis Impacts SEO

This process forms the foundation of SEO strategy. If morphological analysis accuracy is low, your content's true intent won't be correctly communicated to Google. For example, "東京の観光地" (Tokyo's tourist spots) and "東京観光地" (Tokyo tourist spots) carry different meanings, but if the morphological analysis engine misrecognizes these, search results matching user intent may not be generated. Google's search algorithm evolves daily, but Japanese processing complexity remains a significant challenge. Companies entering from other Asian markets must understand this technical background—it directly impacts ranking acquisition in the Japanese market.

Click-Through Rate Statistics and Search Position

Statistical data reveals the practical impact of morphological analysis. The click-through rate difference between positions 1 and 2 is substantial—approximately 39.8% versus 18.7%[1]. This suggests that morphological analysis accuracy significantly affects search rankings, which directly translates to business outcomes. For Japanese SEO, you must ensure clear sentence structure and appropriate keyword placement so Google's morphological analysis engine can accurately understand your content.

The Limitations of Western SEO Tools for Japanese

Why Western Tools Can't Handle Japanese

Most SEO tools are designed with English as the standard and cannot fully capture Japanese complexity. Western tools assume languages with relatively simple word boundary detection, making them incapable of handling Japanese-specific expression formats like compound noun recognition and honorific language. This fundamental difference explains why Asian marketing professionals and Japanese SMBs achieve different results even when using identical tools.

Notation Variations and Compound Noun Recognition Problems

Specifically, Western tools cannot accurately evaluate notation variations like "ECサイト運営" versus "EC サイト運営," or long compound nouns like "Google検索アルゴリズムアップデート" (Google search algorithm update). While Google's algorithm itself continuously improves its Japanese processing capabilities, most SEO tools on the market haven't kept pace with this evolution. Furthermore, Japanese content readability scores fluctuate significantly based on hiragana, katakana, and kanji balance—yet tools considering these Japanese-specific elements remain extremely rare.

The Need for Japanese-Specific Tools

For SMBs to enhance their web competitiveness, strategies based on Japanese processing specifics are essential beyond generic SEO measures. In practice, utilizing Japanese-specific SEO tools or collaborating with consultants possessing language processing expertise is recommended. Understanding this foundation clarifies why compound noun recognition and character balance optimization are particularly important in the Japanese market.

The Importance of Compound Noun Recognition for SEO

What Are Compound Nouns?

Compound nouns are words formed by combining multiple nouns. Expressions like "SEO対策" (SEO measures), "検索アルゴリズム" (search algorithm), and "Webマーケティング" (web marketing) are frequently used in practice, but how Google's algorithm processes these significantly affects SEO success.

Why Compound Nouns Get Overlooked

Western tools fail to accurately recognize compound nouns due to English characteristics. In English, compound nouns are clearly delineated as "compound words" or "noun phrases," but Japanese compound noun boundaries remain ambiguous. For example, when encountering "データ解析" (data analysis), determining whether this combines two independent concepts—"データ" (data) and "解析" (analysis)—or should be treated as a single technical term is mechanically difficult.

Compound Noun Variations and Search Intent

Google's algorithm continues evolving to address this SEO challenge, but many existing tools haven't kept up. In practice, low compound noun recognition accuracy creates situations where expected search results don't appear when users search. Users searching "オンラインショップ開設方法" (how to open an online shop) and "Webストア立ち上げ方法" (how to launch a web store) use different compound nouns but seek identical information. However, conventional SEO strategies don't sufficiently consider these compound noun variations, risking ranking declines.

Practical Strategies for Compound Noun Optimization

Google's search algorithm continues improving Japanese compound noun recognition, and accurate compound noun understanding is expected to become increasingly important as a ranking factor[2]. For companies entering from Asia and Japanese SMBs, understanding this SEO method is key to securing competitive advantage. Practical strategies include using primary compound nouns at appropriate frequency within articles and including synonyms and related terms to assist Google's language understanding.

Optimizing Character Type Balance and Readability Scores

The Ideal Distribution of Hiragana, Katakana, and Kanji

The most significant factor affecting Japanese content readability is the balance of hiragana, katakana, and kanji. Google's search algorithm evaluates "readability scores" as part of its assessment, and this evaluation heavily depends on Japanese-specific character type distribution. Generally, high-quality Japanese content maintains approximately 45-50% kanji, 40-45% hiragana, and 5-10% katakana. This isn't merely aesthetic judgment but scientific knowledge based on reading speed and comprehension for native Japanese speakers.

Specific Methods for Improving Character Balance

As a practical SEO strategy, consciously managing character type balance during writing is essential. For instance, writing "情報処理技術者試験の対策" (information processing technician exam preparation) entirely in hiragana as "じょうほうしょりぎじゅつしゃしけんのたいさく" dramatically reduces readability scores. Conversely, appropriately placing kanji lightens the reader's cognitive load. Statistical data indicates content with optimized readability scores appears in top search results over 70% of the time.

Strategic Approaches to Katakana Usage

Strategic katakana usage is also necessary. Web-related terminology commonly uses katakana spellings like "サーバー" (server), "ブラウザ" (browser), and "キャッシュ" (cache)—forcibly converting these to Japanese alternatives actually reduces readability. Appropriate katakana usage also demonstrates expertise, directly improving user experience.

The Relationship Between Character Balance and Conversion Rates

Character balance optimization affects not only Google algorithm evaluation but also actual user dwell time and conversion rates. Readable content increases the likelihood that users read to the end, consequently creating a positive cycle of maintaining or improving search rankings.

Japanese-Specific Ranking Factors and Optimization Strategies

How Sentence Length Affects Search Rankings

In Japanese content, sentence length significantly impacts search engine evaluation. The "readability" Google's algorithm evaluates isn't merely human perception—it's an indicator objectively measured by machine learning models. For Japanese, sentences of approximately 40-60 characters are generally considered ideal, minimizing user cognitive load while also being effective for SEO. Overly long sentences can cause errors when the morphological analysis engine attempts accurate syntactic understanding, resulting in lower overall content evaluation.

Techniques for Splitting Long Sentences

As a practical SEO method, consciously controlling sentence length during writing is important. For example, a sentence like "Webマーケティング戦略を策定する際には、ターゲットオーディエンスの検索意図を詳細に分析し、そのニーズに合致したコンテンツを複数のチャネルを通じて発信することが、中小企業が検索順位で上位に表示されるための必須条件となります" contains abundant information but reduces readability scores. Splitting this into shorter sentences, each within the 40-60 character range, improves Google algorithm evaluation.

Paragraph Structure Optimization Methods

Paragraph structure is also a critical SEO element. Statistical data shows that over 16% of pages that were outside the top 20 before optimization achieved significant ranking improvements after optimizing paragraph structure[3]. Each paragraph should contain 1-3 sentences as standard, with related information grouped together. Providing appropriate whitespace between paragraphs improves user reading experience, consequently improving scores on the "Needs Met" evaluation criterion.

Conclusion-First Writing Structure

Google's search algorithm tracks user page dwell time and scroll behavior, and good paragraph structure effectively improves these behavioral patterns. In practice, "conclusion-first" structure—presenting the main point at the beginning of each paragraph and explaining details in subsequent sentences—demonstrates high effectiveness for Japanese content.

Heading Hierarchy (H1-H6) Optimization for Japanese

Basic Rules for Heading Hierarchy

Appropriate use of heading hierarchy (H1 through H6) is extremely important for Google's algorithm to understand content structure. While English web content often doesn't strictly follow heading hierarchy, in Japanese SEO, heading hierarchy optimization increasingly correlates directly with search rankings. H1 headings express the overall page theme—placing multiple H1s on a single page should be avoided. H2 headings below indicate main article topics, with H3 and beyond used for detailed explanations. Strictly maintaining this hierarchical structure improves search engine comprehension accuracy.

Designing Headings Based on Search Intent

As a practical SEO method, strongly considering "search intent" when creating headings is required. When users search specific keywords, explicitly showing those needs through heading hierarchy allows Google's search algorithm to improve matching accuracy between content and user search intent. For example, with a theme like "SMB web marketing strategy," H2s should contain specific topics like "Challenges SMBs face," "Practical web-based strategies," and "Concrete methods for improving search rankings." H3s then contain more detailed information like "SEO methods under budget constraints" and "Ranking improvement case studies through heading optimization."

Optimal Character Count for H2 Headings

Heading character count is also an optimization target. Generally, H2 headings of 13-20 characters are ideal, aligning with Japanese reading rhythm. Overly long H2 headings become obstacles when the morphological analysis engine attempts accurate compound noun boundary recognition, potentially distorting content intent.

Correlation Between Heading Hierarchy, Rankings, and Conversions

Statistical analysis shows that content with 390 monthly visitors generating 8 conversions achieves approximately 2% conversion rate. However, pages with improper heading hierarchy that drop to position 5 see traffic decrease to 50 visitors and conversions drop to around 1. In other words, maintaining rankings through heading hierarchy optimization isn't just one SEO method—it's a critical measure directly impacting business results. Asian companies considering web expansion in Japan must understand this heading hierarchy importance and implement proper design from the initial content creation stage.

Building E-E-A-T in the Japanese Market

What Is E-E-A-T?

Building E-E-A-T (Experience, Expertise, Authoritativeness, Trustworthiness) in the Japanese market isn't merely a Google algorithm evaluation criterion—it's a fundamental strategy for Asian companies entering Japan and domestic SMBs to acquire long-term competitiveness.

How to Demonstrate Expertise in Japan

The demonstration of "expertise" differs significantly between Western countries and Japan. In the Japanese market, practical experience and continuous information dissemination tend to be recognized as evidence of expertise, more than company achievements or educational credentials. Google's algorithm comprehensively evaluates information companies publish, citation source reliability, and content depth to determine expertise.

Balancing Technical Terminology and Plain Explanations

As a practical SEO strategy, the following approaches effectively demonstrate expertise. First, accurately use industry-specific terminology while adding plain explanations at first occurrence. For medical field content, when using the technical term "リンパ球" (lymphocyte), adding the supplement "a type of white blood cell responsible for immune defense in the body" achieves both expertise and accessibility.

Building Credibility Through Data and Statistics

Second, present specific data and statistics as evidence. Company case studies demonstrating experience with over 2,000 production and customer acquisition projects providing the latest medical information and practical management strategies serve not as mere boasting but as evidence of professional knowledge meeting reader needs.

The Importance of Regular Content Updates

Additionally, regular information updates are important. Google's algorithm tends to judge sites with abandoned old information as "poorly managed low-quality sites," making content strategies responding to latest industry trends essential. For Asian marketers considering entry into the Japanese market, understanding trust-building element differences by industry leads to effective SEO strategy construction.

Proving Expertise Through Case Studies

As a practical example of content strategy demonstrating expertise, regularly publishing case studies on company blogs is recommended. Including three elements—"specific challenges of implementing companies," "implementation process," and "quantitative measurement of results"—allows readers to acquire practical-level expertise while search engines highly evaluate content value[4]. This strategy directly improves search rankings while also contributing to improved user experience by increasing needs satisfaction (degree of reader problem resolution).

Action Plan for Improving Trustworthiness

The Challenge and Importance of Building Trust

Building "Trustworthiness" in E-E-A-T is both the most difficult and most important part of the strategy. In the Japanese market, transparent information disclosure, consistent messaging, and social trust achievements (customer reputation, industry certifications, media coverage) serve as trustworthiness indicators. Google's algorithm calculates overall site trustworthiness scores by detecting mentions from external sites and third-party evaluation information.

Clarifying Author Information and Contact Details

The first stage of a specific action plan is clarifying author information and contact details. Track records like overseeing response to over 70 clients should not merely be stated on the site but published in industry magazines and media platforms—only then does Google's algorithm recognize and reflect this in trustworthiness scores.

Leveraging Customer Reviews and Third-Party Evaluations

The second stage is visualizing customer testimonials and reviews. Third-party positive feedback carries more persuasive power than company claims, making review management on Google My Business and social platforms important.

Enhancing Security and Privacy Policies

The third stage is enhancing security and privacy policies. Companies entering the Japanese market from Asia can significantly improve trustworthiness by demonstrating strong interest in data protection.

Building Trust Through Free Content

As a specific implementation measure, providing practical free resources like "50 SEO Checklist Items" is recommended. Providing concise, useful content that one person can complete demonstrates both company expertise and helpfulness, making it extremely effective for trust building. Furthermore, hosting regular webinars and speaking at industry events are important measures for enhancing trustworthiness.

The Importance of Continuous Trust Building

Systematically implementing these action plans achieves improved search rankings while building a trustworthy brand meeting user needs. The key to success in the Japanese market lies in balanced SEO strategies simultaneously satisfying both Google algorithm evaluation criteria and actual customer needs. For SMBs and companies entering from Asia, E-E-A-T building cannot be achieved overnight, but through continuous information dissemination and accumulated achievements, trustworthiness can be steadily increased.

Conclusion: Five Keys to Japanese SEO Success

Success in Japanese SEO begins with deeply understanding how Google's search algorithm processes Japanese content. The five important elements explained in this article—morphological analysis, compound noun recognition, character type balance, sentence structure, and E-E-A-T—aren't independent measures but comprehensive SEO strategies that work together to improve both search rankings and user experience.

Challenges for Asian Companies

For companies entering the Japanese market from Asia, the greatest challenge is recognizing the limitations of Western SEO tools and mastering Japanese-specific optimization methods. By understanding how morphological analysis engines work, appropriately placing compound nouns, and optimizing character type balance, you can create an environment where Google's algorithm accurately evaluates your content's value.

Priorities for Japanese Domestic SMBs

For domestic Japanese SMBs, maximizing effects with limited resources requires carefully optimizing basic elements like sentence length, paragraph structure, and heading hierarchy.

Practical Actions You Can Start Today

Practically, start by checking your current web content's character type balance and heading hierarchy. As statistical data shows, dropping from position 1 to position 5 alone significantly reduces traffic and conversions. In other words, Japanese SEO isn't merely search engine compliance—it's a critical business strategy directly impacting results.

Long-Term E-E-A-T Development

From a long-term perspective, E-E-A-T development is most important. Expertise, authoritativeness, and trustworthiness cannot be acquired overnight, but through continuous information dissemination, sincere dialogue with customers, and accumulated achievements, brand value can be steadily increased. Google's algorithm will continue evolving, but prioritizing user needs and continuously providing high-quality content remains the universal strategy adaptable to any algorithm changes.

References

[1] Google検索アルゴリズムとは？6つのSEO対策方法や最新のアップデートについて解説 (Position 1): https://stock-sun.com/column/seo-algorithm/

[2] 【2025年6月最新】Googleコアアップデート情報と取り組むべきSEOを解説 (Position 2): https://www.seohacks.net/blog/14491/

[3] 【2025年3月版】Googleのアルゴリズムとアップデートの傾向!SEO対策に必要なコツも紹介 | Appmart株式会社（アップマート） (Position 3): https://appmart.co.jp/blog/google-algorithm/

[4] 【SEO担当必見】Google検索アルゴリズムとアップデートの歴史 | 株式会社PLAN-B (Position 4): https://www.plan-b.co.jp/blog/seo/206/

[5] Google検索アルゴリズムの仕組みや効果的なSEOなど解説！ (Position 5): https://zeromedical.tv/zeromedical-web/blog/seo-algorithm/

[6] 【2025年12月最新】Googleコアアップデートや主要アップデートの歴史まとめ | WEB集客ラボ byGMO（GMO TECH） (Position 1): https://gmotech.jp/semlabo/seo/blog/googlecoreupdate_history/

[7] Yahoo!の順位と、Googleの順位が違うのはなぜですか？ - SEOよくある質問｜SEO Pack (Position 1): https://seopack.jp/seo_faq/yahoo_google_search_ranking.php